Boosted engine control responsive to driver selected performance

ABSTRACT

Various systems and methods are described for operating an engine in a vehicle in response to a driver performance/economy mode. One example method comprises delivering a first fuel to a cylinder of the engine from a first injector, delivering a second, different, fuel to the cylinder of the engine from a second injector, varying a relative amount of said first and second fuel as an operating condition varies; and adjusting delivery of at least said second fuel based on a driver-selected performance mode.

FIELD

The present description relates to a method for controlling an internalcombustion engine operating with a variety of fuels of varyingcomposition and fuel delivery options.

BACKGROUND AND SUMMARY

Engines may use various forms of fuel delivery to provide a desiredamount of fuel for combustion in each cylinder. One type of fuelinjection, or delivery, uses a port injector for each cylinder todeliver fuel to respective cylinders. Another type of fuel injectionuses a direct injector for each cylinder. Engines have also beendescribed using more than one injector to provide fuel to a singlecylinder in an attempt to improve engine performance.

One such example (U.S. 2007/0119422 A1) describes a flexiblemultiple-fuel engine using both port and direct injection, wheredifferent fuel types are provided to the injectors. For example, directinjection of ethanol may be used with port injected gasoline to addressknock limitations, especially under boosted conditions. In this example,a desired setting for the various fuels may be predetermined usingengine maps, and then adjusted based on feedback from a knock sensor.Specifically, the effective knock suppression of the fuels can be variedresponsive to operating conditions to improve engine efficiency whilemeeting engine output requirements.

However, the inventor herein has recognized several issues with such anapproach. As one example, the above predetermined settings for the fueldistribution may be set based on an average operator driving cycle,where knock sensor feedback is relied upon to address variation in theoperator driving habits. In this case, aggressive drivers mayconsistently experience transient knock before the system can react tothe knock sensor feedback and adjust the fuel injectionlocation/composition to abate the engine knock. Additionally,conservative drivers may consistently experience less fuel economy gainsthan otherwise possible and/or unnecessarily high ethanol consumptionrates.

To address this and other issues, one example approach uses a method foroperating an engine in a vehicle, the method comprising: delivering afirst fuel to a cylinder of the engine from a first injector, deliveringa second fuel to the cylinder of the engine from a second injector,(where, for example, the second fuel has a greater heat of vaporizationthan the first fuel), varying a relative amount of the first and secondfuel as an operating condition varies; and adjusting delivery of atleast the second fuel based on a driver selected engine operating mode.

In this way, it is possible to adjust, for example, both predeterminedfuel injection settings, as well as feedback gains, to better match theengine performance to the driver's selected mode. In the example of aperformance mode setting, the predetermined settings can be adjusted toincrease, at a given speed/load, compared to a fuel economy mode, usageof the fuel providing increased knock suppression capabilities and/or anincreased heat of vaporization. As such, the system may rely less onknock sensor feedback to correct inadvertent knock during transient loadchanges by ensuring sufficient knock suppression is already present.Likewise, in the example of a fuel economy mode setting, thepredetermined settings can be adjusted to decrease the knock suppressioncapabilities of the fuel injection, and rely more heavily on knocksensor feedback. As such, the system may conserve knock suppressioncapabilities until actually needed and use the information of theperformance setting to predict reduced transients.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a vehicle illustrating various componentsof the powertrain system.

FIG. 2 shows an example embodiment of a combustion chamber operatingwith a plurality of fuel injector options.

FIG. 3 shows a high level flow chart for engine running operationsaccording to the present disclosure.

FIG. 4 shows graphs illustrating an example relationship of fuelinjection as a function of the desired torque.

FIG. 5A shows a high level flow chart illustrating an example routinefor boost setting adjustments responsive to a driver selected operatingmode.

FIG. 5B shows a map of minimum boost level settings for a desiredoperating mode.

DETAILED DESCRIPTION

The following description relates to a method for operating an engine ina vehicle wherein an engine control system is configured to adjustengine operating parameters in response to a driver selected mode ofoperation. For example, the driver may indicate a preference towards ahigh performance mode or a fuel economy mode. Based on the modeselection, the control system may better turn vehicle performance to thedriver. Consequently, the control system can better anticipate engineoperating constraints and the engine may be further configured to betterdeal with the anticipated constraints by appropriately adjusting engineoperating parameters. Parameters such as a rate of usage of a fuel withknock suppression capabilities, a minimum boost level, a transmissionshift schedule, for example, may be differently adjusted based onwhether a performance mode or a fuel economy mode is selected.

In one example, the engine may be configured to perform adjustments inanticipation of the constraints in a performance mode, to reducereliance on feedback from the respective constraint related feedbacksensors. In contrast, the engine may be configured to rely more heavilyon feedback sensors for dealing with engine operating constraints in thefuel economy mode. In this way, engine and vehicle performance may becustomized to the driver's driving habits.

FIG. 1 depicts an example embodiment of a vehicle powertrain system 100.As illustrated, an internal combustion engine 10, further describedherein in FIG. 2, is shown coupled to torque converter 22 via crankshaft21. Torque converter 22 is also coupled to transmission 24 via turbineshaft 23. Torque converter 22 has a bypass, or lock-up clutch (notshown) which may be engaged, disengaged, or partially engaged. When theclutch is either disengaged or partially engaged, the torque converteris said to be in an unlocked state. The lock-up clutch may be actuatedelectrically, hydraulically, or electro-hydraulically, for example. Thelock-up clutch may receive a control signal from the controller (asshown in FIG. 2), such as a pulse width modulated signal, to engage,disengage, or partially engage, the clutch based on engine, vehicle,and/or transmission operating conditions.

Turbine shaft 23 is also known as a transmission input shaft.Transmission 24 comprises an electronically controlled transmission witha plurality of selectable discrete gear ratios.

Transmission 24 also comprises various other gears, such as, forexample, a final drive ratio 26. In alternate embodiments, a manualtransmission operated by a driver with a clutch may be used. Further,various types of automatic transmission may be used. Transmission 24 iscoupled to tire 28 via axle 27. Tire 28 interfaces the vehicle (notshown) to the road 30. In one embodiment, powertrain system 100 iscoupled in a passenger vehicle that travels on the road.

FIG. 2 depicts an example embodiment of a combustion chamber or cylinderof internal combustion engine 10. Engine 10 may be controlled at leastpartially by a control system including controller 12 and by input froma vehicle operator 130 via an input device 132. In this example, inputdevice 132 includes an accelerator pedal and a pedal position sensor 134for generating a proportional pedal position signal PP. Cylinder (i.e.combustion chamber) 14 of engine 10 may include combustion chamber walls136 with piston 138 positioned therein. Piston 138 may be coupled tocrankshaft 140 so that reciprocating motion of the piston is translatedinto rotational motion of the crankshaft. Crankshaft 140 may be coupledto at least one drive wheel of the passenger vehicle via a transmissionsystem. Further, a starter motor may be coupled to crankshaft 140 via aflywheel to enable a starting operation of engine 10.

Cylinder 14 can receive intake air via a series of intake air passages142, 144, and 146. Intake air passage 146 can communicate with othercylinders of engine 10 in addition to cylinder 14. In some embodiments,one or more of the intake passages may include a boosting device such asa turbocharger or a supercharger. For example, FIG. 1 shows engine 10configured with a turbocharger including a compressor 174 arrangedbetween intake passages 142 and 144, and an exhaust turbine 176 arrangedalong exhaust passage 148. Compressor 174 may be at least partiallypowered by exhaust turbine 176 via a shaft 180 where the boosting deviceis configured as a turbocharger. However, in other examples, such aswhere engine 10 is provided with a supercharger, exhaust turbine 176 maybe optionally omitted, where compressor 174 may be powered by mechanicalinput from a motor or the engine. A throttle 162 including a throttleplate 164 may be provided along an intake passage of the engine forvarying the flow rate and/or pressure of intake air provided to theengine cylinders. For example, throttle 162 may be disposed downstreamof compressor 174 as shown in FIG. 1, or may be alternatively providedupstream of compressor 174.

Exhaust passage 148 can receive exhaust gases from other cylinders ofengine 10 in addition to cylinder 14. Exhaust gas sensor 128 is showncoupled to exhaust passage 148 upstream of emission control device 178.Sensor 128 may be any suitable sensor for providing an indication ofexhaust gas air/fuel ratio such as a linear oxygen sensor or UEGO(universal or wide-range exhaust gas oxygen), a two-state oxygen sensoror EGO (as depicted), a HEGO (heated EGO), a NOx, HC, or CO sensor.Emission control device 178 may be a three way catalyst (TWC), NOx trap,various other emission control devices, or combinations thereof.

Each cylinder of engine 10 may include one or more intake valves and oneor more exhaust valves. For example, cylinder 14 is shown including atleast one intake poppet valve 150 and at least one exhaust poppet valve156 located at an upper region of cylinder 14. In some embodiments, eachcylinder of engine 10, including cylinder 14, may include at least twointake poppet valves and at least two exhaust poppet valves located atan upper region of the cylinder.

Intake valve 150 may be controlled by controller 12 via actuator 152.Similarly, exhaust valve 156 may be controlled by controller 12 viaactuator 154. During some conditions, controller 12 may vary the signalsprovided to actuators 152 and 154 to control the opening and closing ofthe respective intake and exhaust valves. The position of intake valve150 and exhaust valve 156 may be determined by respective valve positionsensors (not shown). The valve actuators may be of the electric valveactuation type or cam actuation type, or a combination thereof. Theintake and exhaust valve timing may be controlled concurrently or any ofa possibility of variable intake cam timing, variable exhaust camtiming, dual independent variable cam timing or fixed cam timing may beused. Each cam actuation system may include one or more cams and mayutilize one or more of cam profile switching (CPS), variable cam timing(VCT), variable valve timing (VVT) and/or variable valve lift (VVL)systems that may be operated by controller 12 to vary valve operation.For example, cylinder 14 may alternatively include an intake valvecontrolled via electric valve actuation and an exhaust valve controlledvia cam actuation including CPS and/or VCT. In other embodiments, theintake and exhaust valves may be controlled by a common valve actuatoror actuation system, or a variable valve timing actuator or actuationsystem.

Cylinder 14 can have a compression ratio, which is the ratio of volumeswhen piston 138 is at bottom center to top center. Conventionally, thecompression ratio is in the range of 9:1 to 10:1. However, in someexamples where different fuels are used, the compression ratio may beincreased. This may happen for example when higher octane fuels or fuelswith higher latent enthalpy of vaporization are used. The compressionratio may also be increased if direct injection is used due to itseffect on engine knock. In some embodiments, each cylinder of engine 10may include a spark plug 192 for initiating combustion. Ignition system190 can provide an ignition spark to combustion chamber 14 via sparkplug 192 in response to spark advance signal SA from controller 12,under select operating modes. However, in some embodiments, spark plug192 may be omitted, such as where engine 10 may initiate combustion byauto-ignition or by injection of fuel as may be the case with somediesel engines.

In some embodiments, each cylinder of engine 10 may be configured withone or more fuel injectors for providing fuel thereto. As a non-limitingexample, cylinder 14 is shown including two fuel injectors 166 and 170.Fuel injector 166 is shown coupled directly to cylinder 14 for injectingfuel directly therein in proportion to the pulse width of signal FPW-1received from controller 12 via electronic driver 168. In this manner,fuel injector 166 provides what is known as direct injection (hereafterreferred to as “DI”) of fuel into combustion cylinder 14. While FIG. 1shows injector 166 as a side injector, it may also be located overheadof the piston, such as near the position of spark plug 192. Such aposition may improve mixing and combustion when operating the enginewith an alcohol-based fuel due to the lower volatility of somealcohol-based fuels. Alternatively, the injector may be located overheadand near the intake valve to improve mixing. Fuel may be delivered tofuel injector 166 from high pressure fuel system-1 172 including a fueltank, fuel pumps, and a fuel rail. Alternatively, fuel may be deliveredby a single stage fuel pump at lower pressure, in which case the timingof the direct fuel injection may be more limited during the compressionstroke than if a high pressure fuel system is used. Further, while notshown, the fuel tank may have a pressure transducer providing a signalto controller 12.

Fuel injector 170 is shown arranged in intake passage 146, rather thanin cylinder 14, in a configuration that provides what is known as portinjection of fuel (hereafter referred to as

“PFI”) into the intake port upstream of cylinder 14. Fuel injector 170may inject fuel in proportion to the pulse width of signal FPW-2received from controller 12 via electronic driver 171. Fuel may bedelivered to fuel injector 170 by fuel system-2 173 including a fueltank, a fuel pump, and a fuel rail. Note that a single driver 168 or 171may be used for both fuel injection systems, or multiple drivers, forexample driver 168 for fuel injector 166 and driver 171 for fuelinjector 170, may be used, as depicted.

Fuel may be delivered by both injectors to the cylinder during a singlecycle of the cylinder. For example, each injector may deliver a portionof a total fuel injection that is combusted in cylinder 14. Further, thedistribution and/or relative amount of fuel delivered from each injectormay vary with operating conditions. Further still, fuel delivery may bevaried responsive to a driver selected preference for an engineoperating mode, as elaborated herein. The relative distribution of thetotal injected fuel among injectors 166 and 170 may be referred to as aninjection type. For example, injecting all of the fuel for a combustionevent via injector 166 may be an example of a first injection type,injecting all of the fuel for a combustion event via injector 170 may bean example of a second injection type, injecting two-thirds of the fuelfor a combustion event via injector 166 and the other third of the fuelvia injector 170 may be an example of a third injection type, injectinga third of the fuel for a combustion event via injector 166 and theother two-thirds of the fuel via injector 170 may be an example of afourth injection type. Note that these are merely examples of differentinjection types, and various other types of injection and delivery maybe used, and further the approach may be applied to more than twoinjectors as well.

Additionally, it should be appreciated that port injected fuel may bedelivered during an open intake valve event, closed intake valve event(e.g., substantially before the intake stroke), as well as during bothopen and closed intake valve operation. Similarly, directly injectedfuel may be delivered during an intake stroke, as well as partly duringa previous exhaust stroke; during the intake stroke, and partly duringthe compression stroke, for example. As such, even for a singlecombustion event, injected fuel may be injected at different timingsfrom a port and direct injector. Furthermore, for a single combustionevent, multiple injections of the delivered fuel may be performed percycle. The multiple injections may be performed during the compressionstroke, intake stroke, or any appropriate combination thereof.

As described above, FIG. 2 shows only one cylinder of a multi-cylinderengine. As such each cylinder may similarly include its own set ofintake/exhaust valves, fuel injector(s), spark plug, etc.

Fuel injectors 166 and 170 may have different characteristics. Theseinclude differences in size, for example, one injector may have a largerinjection hole than the other. Other differences include, but are notlimited to, different spray angles, different operating temperatures,different targeting, different injection timing, different spraycharacteristics, different locations etc. Moreover, depending on thedistribution ratio of injected fuel among injectors 170 and 166,different effects may be achieved. Fuel tanks in fuel systems 172 and173 may hold fuel with different fuel qualities, such as different fuelcompositions. These differences may include different alcohol content,different octane, different heat of vaporizations, different fuelblends, and/or combinations thereof etc. In one example, fuels withdifferent alcohol contents could include one fuel being gasoline and theother being ethanol or methanol. In another example, the engine may usegasoline as a first substance and an alcohol containing fuel blend suchas E85 (which is approximately 85% ethanol and 15% gasoline) or M85(which is approximately 85% methanol and 15% gasoline) as a secondsubstance. Other alcohol containing fuels could be a mixture of alcoholand water, a mixture of alcohol, water and gasoline etc. In stillanother example, both fuels may be alcohol blends wherein the first fuelmay be a gasoline alcohol blend with a lower ratio of alcohol than agasoline alcohol blend of a second fuel with a greater ratio of alcohol,such as E10 (which is approximately 10% ethanol) as a first fuel and E85(which is approximately 85% ethanol) as a second fuel. Additionally, thefirst and second fuels may also differ in other fuel qualities such as adifference in temperature, viscosity, octane number, latent enthalpy ofvaporization etc.

Controller 12 is shown in FIG. 1 as a microcomputer, includingmicroprocessor unit 106, input/output ports 108, an electronic storagemedium for executable programs and calibration values shown as read onlymemory chip 110 in this particular example, random access memory 112,keep alive memory 114, and a data bus. Controller 12 may receive varioussignals from sensors coupled to engine 10, in addition to those signalspreviously discussed, including measurement of inducted mass air flow(MAF) from mass air flow sensor 122; engine coolant temperature (ECT)from temperature sensor 116 coupled to cooling sleeve 118; a profileignition pickup signal (PIP) from Hall effect sensor 120 (or other type)coupled to crankshaft 140; throttle position (TP) from a throttleposition sensor; and absolute manifold pressure signal (MAP) from sensor124. Engine speed signal, RPM, may be generated by controller 12 fromsignal PIP. Manifold pressure signal MAP from a manifold pressure sensormay be used to provide an indication of vacuum, or pressure, in theintake manifold.

A manually operable performance setting switch 198 may be used by adriver to select a preferred mode of engine operation. The switch mayallow the controller to adjust engine operation settings towards a fueleconomy mode or a performance mode. In one embodiment, switch 198 may bea binary switch allowing the driver a selection among the two modes. Inan alternate embodiment, the switch may be a dial that allows the driverto select among a plurality of degrees within each mode. The switchsetting may be relayed to controller 12 to perform a control systemroutine, as further described in FIG. 3, that adjusts engine operatingparameters, and a fuel injection and/or fuel delivery type, based on theengine operating constraints and the driver selected engine setting.

Engine 10 may further include a fuel vapor purging system (not shown)for storing and purging fuel vapors to the intake manifold of the enginevia vacuum generated in the intake manifold. Additionally, engine 10 mayfurther include a positive crankcase ventilation (PCV) system wherecrankcase vapors are routed to the intake manifold, also via vacuum.

Storage medium read-only memory 110 can be programmed with computerreadable data representing instructions executable by processor 106 forperforming the methods described below as well as other variants thatare anticipated but not specifically listed.

FIG. 3 describes a control system routine for an internal combustionengine affecting engine operating parameters, a fuel type delivered, aswell as the type of injection used, responsive to at least a driverselected engine operating mode. Specifically, the routine determines theengine operation mode setting selected by the driver and accordinglyadjusts usage of a fuel and injection type, and adjusts settings of avariety of engine operating parameters such as valvetrain settings,boost levels, transmission schedules, and deceleration settings, forexample. In doing so, the control system allows engine and vehicleoperation to be customized and optimized based on the driver'spreference towards a higher performance or a higher fuel economy.

At 302, the engine operating conditions are estimated and/or measured.These include, but are not limited to, engine temperature, enginecoolant temperature, engine speed, manifold pressure, air-fuel ratio,equivalence ratio, cylinder air amount, feedback from a knock sensor,desired engine output torque from pedal position, spark timing,barometric pressure, etc.

At 304, the driver selected settings are estimated and a preferredengine operating mode is determined. In one embodiment, this may involveestimating the position of a binary switch indicating a performance mode(“P mode”) or a fuel economy mode (“F mode”). In an alternateembodiment, this may involve determining a degree of performance or fueleconomy selected on a dial. The degrees may be annotated as P1, P2, P3,F1, F2, F3, and so on, based on a configured range of degrees.

Based on the identified current operating conditions, and the driverselected engine operating mode, at 306, a fuel type and injection typeare selected. In one embodiment, two different fuels may be used for thetwo injectors wherein one may be port injected gasoline and the othermay be direct injected E85. A map, as depicted in FIG. 4, may be used togenerate a look-up table and to determine the injection amount anddistribution ratio of fuels responsive to the engine operatingconditions and the driver selected settings. In one example, if thedriver selected settings indicate a preference for the performance mode,the usage ratio of direct injected E85 may be increased vis-a-vis theusage of port injected gasoline. By reading a driver selectedperformance mode, the engine control system may predict constraintsassociated with aggressive driving, such as knocking and exhaustover-temperature conditions. Accordingly, by increasing the use of thedirect injected ethanol based fuel, including at lower speeds/loads, thecontrol system may take advantage of the charge cooling effect ofalcohol, and reduce the constraints anticipated with aggressive driving.As such, the system may then rely less on knock sensor feedback tocorrect inadvertent knock, or a temperature sensor to correctinadvertent over-temperature during transient load changes.

In another example, if the driver selected settings indicate apreference for the fuel economy mode, the usage ratio of direct injectedE85 may be decreased vis-a-vis the usage of port injected gasoline. Byreading the driver selected fuel economy mode, the engine control systemmay predict fewer constraints associated with conservative drivinghabits. Accordingly, the engine operating parameter settings can beadjusted to reserve usage of the direct injected E85 to high loads whileadjusting other engine operating parameters, such as an amount of sparkretard and/or boost, to alleviate knock constraints at low to mediumspeeds/loads. As such, in the fuel economy mode, the routine may relymore heavily on a feedback sensor to manage constraints as they arise,instead of anticipating them and taking early preventative steps. Inthis way, based on the selected mode, the control system may provide thedriver with enhanced performance while preferably consuming the portinjected gasoline and while deferring usage of the direct injectedalcohol.

At 308, a knock sensor is read. If an indication of knock is received,then at 310, an increased injection of the fuel with a higher heat ofvaporization and providing knock suppression capabilities ensues. Byadjusting fuel injection responsive to feedback from a knock sensor, theroutine may adjust knock variations arising from temporary load changes.Thus, in a fuel economy mode, the engine may be configured to respondmore heavily to feedback from a knock sensor. In contrast, in aperformance mode, the engine may be configured to anticipate knock evenat lower speeds/loads and assign a fuel injection ratio accordingly, andto further adjust fuel adjustments based on feedback data from a knocksensor to adjust temporary knock transients.

At 312-318, a variety of engine operating parameters are similarlyadjusted based on the driver selected setting, and further based on thefuel injection settings from 306. For example, these adjustments may bebased on the predetermined settings as read from a lookup table, forexample. Accordingly, at 312, the transmission shift schedule may beadjusted. In one example, when an F mode is selected, the control systemmay perform an earlier transmission shift, at lower speeds while, when aP mode is selected, the control system may delay the transmission shiftto allow for a maximum acceleration to be produced.

At 312, the torque converter lock-up schedule may be adjusted responsiveto the chosen operating mode. In one example, when an F mode isselected, the control system may cause engagement of the torqueconverter lock-up clutch in order to maximize torque converter lock up.Furthermore, the control system may maintain the torque converter in anengaged (or locked) state for a greater amount of time. In doing so, theslip frequency and power losses in the torque converter may be reduced.In another example, when a P mode is selected, the control system maycause disengagement or partial engagement of the torque converterlock-up clutch in order to reduce torque converter lock up. Furthermore,the control system may maintain the torque converter in a disengaged (orunlocked) state for a greater amount of time.

At 316, a boost level may be adjusted responsive to the chosen operatingmode. For example, the control system may maintain boosting above aminimum boost level, such as during idle conditions to reduce turbo lag.In one example, for a desired torque, when an F mode is selected, thecontrol system may reduce the minimum boost level while when in a Pmode, the control system may increase the minimum boost level. Theminimum boost level may be adjusted by adjusting throttle position, latefuel injection (which adjusts exhaust heat), etc.

Further, the minimum boost level may further be adjusted in coordinationwith the fuel injection settings of 308, such that the increased minimumboost is used with a more aggressive use of fuel-based knocksuppression. Additional details of this operation are described withregard to FIG. 5.

At 318, other engine operating parameters are adjusted, for examplevalvetrain settings, VCT settings, exhaust gas recirculation (EGR)settings, throttle settings, and deceleration settings, based on thedriver selected engine operating mode. In this way, by adjusting theengine operation settings, such as spark timing, boost level, wastegateposition, bypass valve position etc, and further adjusting usage of thefuels based on the driver's preferred engine performance mode, thecontrol system may achieve improved engine performance and improved fueleconomy gains. It will be appreciated that further feedback data from avariety of sensors may be used by the control system to further adjustsettings in each mode. Referring now to FIG. 4, it depicts example mapsof the desired fuel type based on a desired engine output and based onthe engine operating mode selected, for a flexible multiple-fuel engineoperating with a port fuel injection of gasoline and a direct injectionof an ethanol based fuel, such as E85. In particular, FIG. 4 shows theinjection amount of gasoline and ethanol fuels, at 400 a and 400 brespectively, for a desired torque amount, based on whether aperformance mode (solid lines) or a fuel economy mode (dashed lines) isselected. As illustrated by solid lines 402 a and 402 b, as the desiredtorque increases in the performance mode, the fuel type shifts fromprimarily port injected gasoline towards primarily direct injectedethanol. The increased use of the ethanol based fuel at higher torquesallows the system to take advantage of the charge cooling effects ofalcohol. An aggressive use of alcohol, as depicted by the steeper slopeof the solid lines, allows for reduction of constraints associated withhigh performance engine operations such as exhaust over-temperatureconditions and knock conditions, for example. While a similar pattern ofusage is shown in the fuel economy mode at 404 a and 404 b, the moreconservative use of alcohol, as depicted by the shallower slope of thedashed lines, allows the alcohol to be conserved for use at a latertime, such as during an unexpected knock constraint, or alternately,when the driver changes his operating mode selection. In this way, fuelinjection ratios may be calculated based on the anticipated constraintsassociated with the driver's selection of engine setting. By adjustingthe fuel ratio, the various and frequent constraints may be pre-emptedin a performance mode setting. In contrast, the fewer and less frequentconstraints associated with the fuel economy mode may be addressed on anas need basis.

It should be noted that in addition to the mapping of FIG. 4, additionaladjustment of the fuel injections in either mode may be based onfeedback from a knock sensor, as indicated in FIG. 3 at 308. Transientknock constraints, as may occur during transient load changes, and asmay not be anticipated by the control system, may be addressed by atransient increase in direct injection of the ethanol based fuel,responsive to knock indication from a feedback sensor. However, giventhat in the fuel economy mode the control system anticipates fewer knockconstraints and uses the ethanol fuel less aggressively, transient knockspikes and corresponding direct injection of ethanol spikes may, in oneexample, occur more frequently, and also at lower speeds/loads comparedto the performance mode. Further, in one example, the feedback gainsrelating the knock sensor feedback and the corresponding increase indirect injection may be higher in the performance mode than in the fueleconomy mode, to thereby more aggressively respond to any inadvertentengine knock.

In this way, by dynamically changing engine operating parameters andfuel usage in response to a driver selected preferred engine operatingmode, constraints affected by the driver's driving habits may be betteranticipated and managed.

FIG. 5 illustrates an example of the adjustments that may be performedwith regards to boost settings based on a driver mode selection.Specifically, FIG. 5A depicts a boost adjustment routine 500 that may beperformed by the control system in response to a driver mode selection,based on the settings specified in a “boost map”, as depicted in FIG.5B.

At 502, as in 302, the engine operating conditions are estimated and/ormeasured. Next, the driver's selection of engine operation mode isdetermined. Accordingly, at 504, it is determined whether the driver hasselected a performance mode. If yes, then at 506, the control systemadjusts fuel and injection type settings so that a higher ratio ofdirect injected ethanol (or an ethanol based fuel) may be preferentiallyused at respectively lower speeds/loads. The selection of a performancemode enables the control system to anticipate related constraints, suchas higher knock and higher exhaust temperatures even at lowerspeeds/loads. Thus, by appropriately adjusting the fuel and injectionratio towards a higher use of alcohol at the lower speeds, the controlsystem may avert some of these constraints and/or deal with otheremerging constraints more effectively. At 508, the control systemadjusts the minimum boost level of the turbocharger, based on thesettings of map 550 (FIG. 5B). In one aspect, the mapped data from map550 may be translated into a lookup table that may be used by thecontrol system to assign a minimum boost level. The minimum boost levelmay be adjusted by adjusting throttle position, late fuel injection(which adjusts exhaust heat), etc. Alternatively, the turbochargersettings may be appropriately adjusted to allow a higher minimum amountof intake air pressure to be maintained. In doing so, the control systemmay be able to more quickly respond to the driver's demand for highengine output as and when requested. In this way, fuel injectiontype/location may be coordinated with the higher minimum boost level toreduce the potential for engine knock once the driver tips in to thepedal.

If at 504, the performance mode is not selected, then at 510, the systemverifies if a fuel economy mode was selected. If yes, then at 512, thecontrol system adjusts fuel and injection type settings so that a lowerratio of direct injected ethanol may be preferentially used at the lowerspeeds/loads. The selection of a fuel economy mode enables the controlsystem to be coordinated with conservative driving habits and hence toanticipate fewer performance-related constraints. Consequently, thecontrol system may readjust settings to allow a more conservative use ofthe ethanol fuel overall. At 514, the control system further adjusts theminimum boost level, based on the settings of map 550 (FIG. 5B), to alower minimum boost level since the control system anticipates fewerrequests for high engine output.

At 516, irrespective of the engine operating mode selected by thedriver, a feedback knock sensor is read to determine if there is anyindication of knock. If any knock is indicated, this may be addressed at518 by transiently increasing a direct injection of ethanol (or theethanol based fuel).

FIG. 5B illustrates map 550 depicting a variation in minimum boostlevels as a mode selection is changed. Map 550 may be used by thecontrol system when performing boost routine 500. Equivalent maps forother engine operating parameters may be used by the control system forappropriately adjusting the parameter settings responsive to thedriver's selection. The data of the maps may be configured into a lookuptable wherefrom the control system may read and adjust settings inroutine 300 and 500. As illustrated in FIG. 5B, as a mode selectionmoves from a fuel economy mode towards a performance mode, the minimumboost level is raised and consequently a intake manifold pressure isachieved by the turbocharger to enable the engine to provide a fasterresponse to a request for higher engine output.

In this way, an engine operating mode selection indicated by the driversuggests potential constraints and demands to the control system whichmay then adjust engine operation settings appropriately. By anticipatingmode specific constraints and demands, and adjusting engine parametersaccordingly, and by further adjusting the parameters in response tofeedback data from a knock sensor, the control system addresses engineoperating transients and matches engine performance to the driver'sselection more effectively.

Note that the example control and estimation routines included hereincan be used with various system configurations. The specific routinesdescribed herein may represent one or more of any number of processingstrategies such as event-driven, interrupt-driven, multi-tasking,multi-threading, and the like. As such, various actions, operations, orfunctions illustrated may be performed in the sequence illustrated, inparallel, or in some cases omitted Likewise, the order of processing isnot necessarily required to achieve the features and advantages of theexample embodiments described herein, but is provided for ease ofillustration and description. One or more of the illustrated actions,functions, or operations may be repeatedly performed depending on theparticular strategy being used. Further, the described operations,functions, and/or acts may graphically represent code to be programmedinto computer readable storage medium in the control system

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,1-4, 1-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and nonobvious combinationsand subcombinations of the various systems and configurations, and otherfeatures, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations andsubcombinations regarded as novel and nonobvious. These claims may referto “an” element or “a first” element or the equivalent thereof. Suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.Other combinations and subcombinations of the disclosed features,functions, elements, and/or properties may be claimed through amendmentof the present claims or through presentation of new claims in this or arelated application. Such claims, whether broader, narrower, equal, ordifferent in scope to the original claims, also are regarded as includedwithin the subject matter of the present disclosure.

1-20. (canceled)
 21. A method for operating a vehicle's boosted engineand transmission, comprising: delivering a first fuel to a cylinder ofthe engine from a first injector; delivering a second, different, fuelto the cylinder of the engine from a second injector, varying a relativeamount of said first and second fuel as an operating condition varies;and adjusting delivery of said second fuel, a transmissionshift-schedule, and a minimum boost based on a driver-selectedperformance mode.
 22. The method of claim 21 where the second fuel has agreater heat of vaporization than the first fuel.
 23. The method ofclaim 21 where the second fuel includes alcohol, and where the secondfuel is directly injected to the cylinder.
 24. The method of claim 23where the first fuel is port injected to the cylinder.
 25. The method ofclaim 21 where delivery of the first and second fuels is adjusted basedon the driver-selected performance mode, and where said adjustingincludes increasing the relative amount of the second fuel during anincreased vehicle performance mode, and decreasing the relative amountof the second fuel during an increased fuel economy mode.
 26. The methodof claim 25 further comprising adjusting feedback adjustment of thesecond fuel based on the driver-selected performance mode.
 27. Themethod of claim 26 wherein the turbocharger operation adjustmentincludes increasing a minimum boost of the turbocharger during theincreased vehicle performance mode, and decreasing the minimum boostduring the increased fuel economy mode.
 28. The method of claim 21wherein the operating condition includes engine load.
 29. A method foroperating a vehicle's engine cylinder, comprising: delivering a firstfuel to the cylinder from a first injector; delivering a second fuel tothe cylinder from a second, direct, injector; varying a relative amountof said first and second fuel as an engine boost varies; and adjustingthe boosting by increasing a minimum boost during an increased vehicleperformance mode, and decreasing the minimum boost during an increasedfuel economy mode.
 30. The method of claim 29 where delivery of thefirst and second fuels is adjusted based on the driver-selectedperformance mode, and where said adjusting includes increasing therelative amount of the second fuel during an increased vehicleperformance mode, and decreasing the relative amount of the second fuelduring an increased fuel economy mode.
 31. The method of claim 30wherein the minimum boost is maintained by increasing exhaust gastemperature via a late fuel injection from direct injection of thesecond fuel.
 32. The method of claim 31 where the second fuel has agreater heat of vaporization than the first fuel.
 33. The method ofclaim 32 where the second fuel includes alcohol.
 34. The method of claim33 where the first fuel is port injected to the cylinder.
 35. The methodof claim 29 further comprising increasing feedback adjustment of thesecond fuel during the increased vehicle performance mode.
 36. A methodfor a vehicle's boosted engine cylinder and transmission, comprising:delivering a first fuel to the cylinder from a first injector;delivering a second, different, fuel to the cylinder from a second,direct, injector, varying a relative amount of said first and secondfuel as an operating condition varies; and adjusting delivery of saidsecond fuel, a transmission shift-schedule and torque converter lock-upschedule, and a minimum boost based on a driver-selected performancemode.